Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hanh vai » hanh vi, hanh va, hanh tai
vai cua » dai cua, hai cua, lai cua
sach ty » sach y, sach thu, xach tay
van cam » van nam, van lam, van cau
nang xa » nang x, lang xa, nang ma
sach tu » sach thu, cach tu, sach uu
cua tre » cua te, cuu tre, cua triet
xac va » tac va, ac va, bac va
tuc va » thuc va, truc va, tuc xa

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sach ty) or (sach tu)) nang xa hoi. hieu van cam ((xac va) or (tuc va)) hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ty) OR (sach tu)) nang xa hoi. hieu van cam ((xac va) OR (tuc va)) hanh vai cua tre.
• Adding a wildcard symbol may retrieve word variants: su ((sach ty) or (sach tu)) nang xa hoi. hieu van cam ((xac va) or (tuc va)) hanh vai cua tre*.